1. Field of the Invention
The present invention relates generally to semiconductor manufacturing and, more particularly, to apparatus for shielding access openings from electrical fields, wherein the access openings allow access to semiconductor manufacturing chambers, the electric fields are applied to the chambers adjacent to the access openings, and the access openings provide access for exemplary gas injectors and process analysis and measurement tools.
2. Description of the Related Art
Vacuum processing chambers have been used for etching materials from substrates, and for deposition of materials onto substrates, and the substrates have been semiconductor wafers, for example. U.S. Pat. No. 6,230,651 to Ni et al. issued May 15, 2001 and assigned to Lam Research Corporation, the assignee of the present application, is incorporated herein by reference and illustrates an opening, or port, providing access to an interior of such a processing chamber. There, a gas injection system is used with an RF energy source in the form of a coil mounted externally of the chamber on a dielectric window at the top of the chamber. In one embodiment, an injector of the gas injection system was separate, inserted in the port, and sealed. The injector supplied process gas to the chamber. The RF energy from the coil energized the process gas to provide a plasma in the chamber for processing the substrate. For the gas supply, the injector was configured with many gas outlets, including embodiments with eight or nine gas outlets. The gas outlets were located in a region of reduced electric field strength to reduce susceptibility to clogging. Such clogging was related to a thin plasma sheath which could cause electric field lines created by a difference in potential between the plasma and a grounded injector tube.
U.S. Pat. No. 6,013,155 to McMillin et al. issued Jan. 11, 2000, and also assigned to Lam Research Corporation, is incorporated herein by reference and illustrates other openings, or ports, providing access to an interior of such a processing chamber. One showerhead injector described in the McMillin Patent is a composite coaxial structure formed by an inner metallic liner inserted into the interior of a dielectric tube.
These patents improved access to such processing chambers. However, as industry standards have increased, further improvements are required to provide even better access to such processing chambers. For example, in the experience of the applicants of the present application, further improvements are required in each of the elements that provide such access. Such improvements may include port configuration, injector configuration, shield configuration for improved protection from electric fields, and better grounding techniques, for example.
In view of the foregoing, there is a need for apparatus providing further improvements to each of the elements that provide access to processing chambers. Such improvements include port configuration, injector configuration, shield configuration for improved protection from electric fields, and better grounding techniques. Exemplary needs identified by the present applicants include configurations that increase ease of use and reliability of retaining the shield and injector in the port without compromising window structural integrity or the sealing of the injector to the window, for example, while reducing the impact of the electric field on these elements.